For example, a film capacitor is constructed of a dielectric film of polypropylene resin in film-like form having a vapor-deposited metallic membrane on its surface as an electrode. With this construction, in the event of electrical short-circuiting in an insulation defective area of the dielectric film, the metallic membrane located around the defective area is vaporized for release under short-circuiting-induced energy, causing electrical insulation, with the consequence advantage to prevent dielectric breakdown of the film capacitor (for example, refer to Patent Literature 1).
The film capacitor is hence capable of preventing ignition and electric shock entailed by electrical short-circuiting in an electric circuit. The film capacitor, being noteworthy for such a capability, in recent years, has been put to an increasingly wider range of applications, including application to a power circuit of LED (Light Emitting Diode) illumination (for example, refer to Patent Literature 2).
However, on a substrate on which various electronic components are mounted, the film capacitor still has a large size as compared with other electronic component such as a ceramic capacitor. For the purpose of accomplishment of low-profile design and higher packaging density of the substrate, studies have been carried out on development of a smaller version of the film capacitor.
Further, in association with size reduction of electronic equipment, and capacity enhancement of capacitors, and the like, operating environments are becoming a high temperature. Film capacitors are required to have a heat resistance so that stable electrical characteristics may be obtained over a long time even under such conditions.
Employable means for size reduction of a film capacitor includes: layer thickness reduction of the dielectric film; and reduction of the number of stacked layers or the number of winding turns of the dielectric film.
For example, in materials such as polyphenylene ether (PPE) good in the heat resistance and the electrical characteristics, layer thickness reduction is achieved by being mixed with other resins so as to be used as a resin composition material (for example, see Patent Literature 2).